Many times the plasterer is called upon to repair badly cracked ceilings and walls. Heretofore, this has been a time consuming and unreliable operation. Many times, after the restoration has been completed, cracks will develop again even though the workmanship has been good in the plaster restoration. The fault often lies with the building structure rather than with the skill of the plasterer.
The prior art has dealt with the problem of recurring cracks by completely replastering the area of the cracked plaster. For the type of crack that is only slightly visible, an area of the plaster about thirty (30) inches wide and extending beyond the length of the crack is removed down to the laths. The area is then replastered by browning and finishing as in new work. Large wide cracks such as those that recur during the dry heated season of the year have heretofore been dealt with by completely relathing and replastering the entire ceiling or wall by nailing furring strips at right angles to the joists over the old laths and plaster. New laths are applied to the furring strips and the area is then plastered as if it were new work. The purpose of the new furring strips and laths is to spread the movement of a joist over a larger area with the expectation that any excessive deflection will be relieved at a wall angle where it may be hidden by a molding or may not be objectionable if visible. The time and expense of furring and relathing is eliminated by the present invention.
The closest prior art known to applicant is the GLID-WALL FIBERGLASS WALL SYSTEM marketed by Glidden Coatings and Resins, a division of SCM Corporation, Cleveland, Ohio 44115. Published literature on the GLID-WALL SYSTEM explains that it is applied over existing plaster which is badly cracked by first scraping the peeled paint and plaster from the wall and then filling the cracks and voids with a latex patching compound. Next, a vapor barrier primer-sealer is applied to a forty-eight (48) inch wide wall section from ceiling to baseboard and correspondingly sized strips of fiberglass are pressed against the wet sealer coat using a dry roller or wallpaper smoothing tool to smooth the fiberglass onto the wall while removing all air bubbles to create a tight bond. The adhesive vapor barrier primer-sealer coat is then applied to the next forty-eight (48) inches of wall area and a second forty-eight (48) inch wide strip of fiberglass is pressed onto the wall, overlapping the first strip of fiberglass by several inches. The overlapping edges are cut away and the remaining cut edges are meshed into one piece. The two strips of completed fiberglass panels are then saturated with a coat of the vapor barrier primer-sealer to seal the pores in the material and create a smooth primed surface ready to accept a finish coat of paint.
One difficulty with the GLID-WALL SYSTEM is that the resulting surface is a textured surface, lacking the conventional and accepted smoothness of plaster, because the fiberglass has a minimum thickness of twenty-two (22) mils and its texture cannot be covered by two coats of paint.
The Tuff-Kote Company, Inc. of Woodstock, Ill. markets a fiberglass screen-like mesh having a thickness of four (4) mils and various sizes up to twelve (12) square feet for use with a special joint compound or mastic it markets under the trademarks KRACK-KOTE, TUFF-KOTE and TUFFGLASS. The label on the KRACK-KOTE mastic informs the user to "Always Use With TUFFGLASS Fabric", and explains that the result of proper application is to bridge wall and ceiling cracks instead of filling them. The TUFF-KOTE products are intended for use in the repair of cracks in plaster, masonry and wood. KRACK-KOTE mastic and TUFFGLASS fabric are used in repairing wall and ceiling cracks. The fabric is four (4) mils thick, three and three-fourths (33/4) inches wide and thirty-six (36) feet long. The printed directions call for the edges of the crack to be smoothed and cleaned and a sealer to be applied to the crack before applying the special KRACK-KOTE mastic. The KRACK-KOTE mastic is applied liberally, covering the crack and about two and one-half (21/2) inches on each side of the crack. A strip of the TUFFGLASS fabric is embedded in the mastic and excess mastic is removed by wiping out the wrinkles and excess material with an applicator so that the fabric is tight against the wall surface and the meshes filled with mastic. The first coat of mastic is allowed to dry and a second coat is brushed on lightly and the edges are feathered to make a smooth uniform surface with the wall or ceiling. Prime and finish coats of paint are then applied to complete the job.
There is no suggestion in the TUFF-KOTE literature of using the KRACK-KOTE system for the repair of map cracking or restoring a complete wall. The twelve (12) square foot piece of TUFFGLASS fabric is sold with TUFF-KOTE mastic labelled "For External Use" and described as being useful for patching roofs, weatherproofing wood, repairing gutters, and waterproofing masonry. Again, there is no suggestion of using it for repairing map cracking or restoring a complete wall. TUFF-KOTE, KRACK-KOTE, and TUFFGLASS are trademarks of Tuff-Kote Company, Inc., Woodstock, Ill.